Artificial heart valve



March 26, 1968 F. R. ALVAREZ DIAZ 7 3,374,489

ARTIFICIAL HEART VALVE Filed March 26, 1965 INVMOR FRANCISCO RIPERTOALVAREZ DMZ MJA' ATTORNEYS United States Patent 3,374,489 ARTIFICIALHEART VALVE Francisco R. Alvarez Diaz, Antonio Arias 12, Madrid, SpainFiled Mar. 26, 1965, Ser. No. 442,897 Claims priority, applicationSpain, Apr. 7, 1964, 298,382 12 Claims. (Cl. 3--1) ABSTRACT OF THEDISCLOSURE An artificial mitral valve for intracardiac implantationincludes a ring constituting a valve seat having an outer portion forsuturing in position, and a disc-shaped valve member loosely connectedwith said ring to oscillate between open and closed positions.

BACKGROUND OF THE INVENTION The only effective treatment for numeroussufferers from mitral insufiiciently or calcified mitral stenosis,comprises the implantation of an artificial mitral valve, without whichsuch sufferers will die within a relatively short period of time. Theideal type of artificial mitral valve would necessarily have certaindefinite character: istics, namely: it would be absolutely eflicient; itwould not cause stenosis, but would permit sufiicient free flow of bloodto the ventricle, namely at least 15 litres per minute and equal to thevolume delivered by the left ventricle under semiforced workingconditions; articulation of the valve should be by a simple, free andsafe mechanism avoiding thrombosis; it should not protrude more than 1.5centimetres into the left ventricle; it should not produce heamolysis;there should be no dead spaces that would cause thrombosis; it shouldincorporate a safe fastening mechanism, and it should be constructed ofinert, perfectly tolerated material.

With the object of devising the artificial mitral valve which willcomply with all these conditions, intensive work is being carried out atvarious centers. In this way, various models have been produced, each ofwhich endeavors to overcome one of the disadvantages of previousdesigns, but up to the present time the ideal construction has not beenfound. In the last four years, numerous valvular prostheses have beenreported, but none of these have been adequate to be regarded as thedefinitive solution.

In the year 1960, a valve appeared but it has the followingdisadvantages: it is situated entirely in the left ventricle, so that itinterferes with the tract running from the ventricle to the aorta, inmany cases making contact with the wall of said tract and thus causingsubendocardial hematomas, giving rise to arrhythmias and sometimes toventricular fibrillation and the death of the patient. Blood does notpass rapidly and freely to the ventricle, and on occasion theheaemolyses produced are considerable through the friction of the bloodthrough the box.

In an attempt to overcome these disadvantages in the year 1962, anothervalve was produced but it has the disadvantage that it causes rapid andintense thrombosis because the support of a central rod is fixed, sothat patients have to spend their entire life under anticoagulantmedication with the consequent risk of hemorrhage.

In the year 1963, still another mitral valve was produced, havingcertain advantages over previous designs, but has the great disadvantagethat it has the effect of producing stenosis since the passage of bloodis not free.

All other valvular prostheses reported have even greater disadvantages,and at the present time most of this work has been abandoned. Of thethree valves referred to above, the first mentioned valve is at thepresent time used almost throughout the world, despite its seriousdisadvantages, because other valves, which have the same disadvantages,have not been successful.

SUMMARY OF THE INVENTION Briefly, an artificial mitral valve forintracardiac implanation, according to the invention, includes a ringconstituting a valve seat having an outer portion for suturing inposition, and has a pair of inward projections, and a biconvexdisc-shaped valve member having a pair of columns extending from oneface thereof through said ring respectively adjacent said projections,said columns terminating in angled end portions loosely overlying theopposite side of said ring from said valve member and permitting thelatter to oscillate between open and closed positions.

The structure is formed of inert material that is perfectly tolerated bythe patients heart upon implantation, is absolutely efficient and safeand has no deleterious effects, is easily implanted and has a simple andsafe mounting and has a simple articulation mechanism capable ofconstant movement and free of dead spaces,

BRIEF DESCRIPTION OF DRAWING The novel features that are consideredcharacteristic of the invention are set forth with particularity in theappended claims. The invention itself, however, both as to itsorganization and its method of operation, together with additionalobjects and advantages thereof, will best be understood from thefollowing description of a specific embodiment when read in connectionwith the accompanying drawing, wherein like reference charactersindicate like parts throughout the several figures and in which:

FIG. 1 is a plan view of a support ring for an artificial mitral valvein accordance with the present invention;

FIG. 2 is a cross-sectional view taken on line 22 of FIG. 1;

FIG. 3 is an enlarged fragmentary plan view of a portion of the ring andone of the mounting stops;

FIG. 3' is a cross-sectional view taken on line 33' of FIG. 3;

FIG. 4 is a plan view of the valve element for an artificial mitralvalve in accordance with the invention;

FIG. 5 is a side view of the valve element shown in FIG. 4;

FIG. 5' is a side view of the valve element similar to that of FIG. 5,but oriented substantially 45 as in the DETAILED DESCRIPTION OFINVENTION Referring now to the drawing in detail, an artificial mitralvalve according to the invention comprises two parts; a mounting ring 1,FIG. 1, and a flattened biconvex cushion-shaped valve element 8, FIG. 4,which is articulated on and supported by said ring 1, as shown in FIG.6. The mounting ring 1 comprises a base ring 2 and the latter as well asthe valve element 8 are made of inert materials which are perfectlytolerated by the human body.

The ring 2, FIGS. l-3, is circular in shape with smooth flat sides thattaper inwardly to an inner wall 3 having a diameter varying between oneand three centimetres, while, depending on the diameter, its widthvaries between three and six millimetres. The outer periphery of saidring 2 is provided with a V-shaped channel formed by two rims 4, one atthe top and the other at the bottom, both being oblique and convergingtowards the center of the Patented Mar. 26, 1968' ring. At their outeredges, the rims 4 are about six millimetres apart, and the width of theinner face of the rim is from one to four millimetres.

Protruding inwardly from the inner wall 3 of the ring 2 are two stops 7of triangular shape, FIG. 3, situated one on each side of the ring at adistance of about two millimetre-s from a diametrical axis XX, FIG. 1.The channel in the outer periphery contains a second ring 6 of amaterial capable of being pierced by a needle and of holding sutures forthe fastening of the ring 1 in position, this second ring 6 being fixedin the channel by means of an embedded stainless steel wire 5. The ring6 maybe in the form of a mesh or the like and of a mate- 1gial that isinert and is perfectly tolerated by the human ody.

The valve element 8 has a flattened biconvex body having a bottom orventricular face 11, and an upper or auricular face 10. The ventricularface is of circular shape, smooth, with slight convexity; while theauricular face is likewise convex, with two columns 9 situatedeccentricaliy on a line YY, FIG. 4, disposed perpendicularly one thirdalong the length of the diameter Z-Z. These columns extend upwardly fromthe body adjacent the periphery thereof and have angularly disposed freeend portions 9 extending toward the body periphery.

The columns 9 are slightly conical with their outside edgessubstantially perpendicular to the medial plane P-P of the body 8, FIG.5, and the axes B--B of the columns, FIG. are inclined outwardly atabout 100115 relative to said plane, said columns being of greater widthat their bases joined to the body. The outer free ends 9' of the columnsextend at right angles to the inclined inner edges of the columns, andpoint outwards at an angle of about to the line YY, FIG. 4, passingthrough the axes of the columns.

The valve element 8 is articulated to the mounting ring 1 by means ofthe columns 9 which are disposed within the ring 1, and with their freeends 9 overlying one side of the ring. The columns 9 are partiallystraddled by the stops 7, respectively, to prevent relative rotationalmovement. The height of the columns is slightly greater than thethickness of the ring 1 so that the valve element 8 is capable ofmovement in the perpendicular direction of about four to eightmillimetres, depending on size, and the eccentric disposition of thecolumns enables movementin the diagonal direction, as shown in FIG. 6,of one to two centimetres.

The circular shape of the columns 9 and the triangular configuration ofthe stops 7 precludes dead spaces that are unaffected by the oscillatorymovement between these parts caused by the oscillation of the valveelement 8. Thus, the articulation mechanism is safe and simple inoperation and capable of constant movement, thereby precludingthrombosis.

As previously stated, the valve parts are made of inert material that isperfectly tolerated -by the human body. Preferably, the carrier ring 1and valve element 8 are made of synthetic elastomers which havesufiicient rigidity to prevent undesired deformation, but havesufficient elasticity or resilience to enable insertion of the columns 79 within the ring 1. Suitable materials for these parts arepolypropylene or Silastic (W. A. Cleary Corp., New Brunswick, N.J.). Theouter or anchor ring 6 may be formed of Teflon or Dacron (E. I. du Pontde Nemours & Co., Inc., Wilmington, Del.) or Terylene (Imperial ChemicalIndustries Ltd., Imperial Chemical House, Milbank, London, England).

This valve is constructed in different sizes, namely with inside ringdiameters of 1.75, 2.25, 2.50, 2.75 and 3 centimetres.

In use, the valve assembly is implanted surgically in place of a scarredand damaged mitral valve between the left auricle and the leftventricle. The damaged mitral valve is excised and the outer or anchorring 6 is sutured within the opening from which the mitral valve hasbeen excised. The valve is disposed on the ventricalside of the ringwith the face 11 of the valve element 8 toward the ventrical, and theface 10 toward the auricle. The ring 1 then constitutes the valve seatfor the valve element 8, and its inner periphery 3 the valve passageway.

The mitral valve according to the present invention complies with allthe conditions required for a rigid mitral valve, having greatadvantages and no disadvantage. In numerous experimental studies and inspecial valve testing apparatus (duplicator), it has been found thatthis valve is:

(1) Absolutely eflicient.

(2) It does not cause stenosis. It passes 30 litres per minute, so thatthe margin of reserve is 15 litres because, as has been indicated, theactual requirement is 15 litres per minute.

(3) Its articulation mechanism is safe and simple articulation and inconstant movement.

(4) It does not cause haemolysis.

(5) It does not cause thrombosis (simple articulation mechanism inconstant movement and without dead spaces).

(6) Its fastening mechanism is safe.

(7) The material used is inert and perfectly tolerated by the humanbody.

Although a certain specific embodiment of the invention has been shownand described, it is obvious that many modifications thereof arepossible. The invention, therefore, is not to be restricted exceptinsofar as is necessitated by the prior art and by the spirit of theappended claims.

What I claim is:

1. An artificial heart valve for intracardiac implantation comprising acarrier ring defining a valve passageway and a valve seat one one sideof said ring, and a disc-shaped valve element having a diameter greaterthan that of said passageway and having one side engageable with saidseat, two columns projecting from said one side of said valve elementthrough said passageway and having end portions overlying the side ofsaid ring opposite said seat to retain said element and ring inassembled relation, said columns having a length greater than thethickness of said ring to permit movement of said element relative tosaid ring, and said carrier ring having two projections extendinginwardly into said passageway and respectively engaging said columns tosteady said valve element in relation to said ring and to obstructrotational displacement of said valve element relative to said ring butpermitting free movement of said valve element toward and from saidseat.

2. A heart valve according to claim 1 wherein said columns areeccentrically disposed relative to said one side of said valve elementso that the movement thereof is oscillatory in both an axial and anangular direction.

3. An artificial heart valve for intracardiac implantation comprising acarrier ring defining a valve passageway and a valve seat on one side ofsaid ring, and a discshaped valve element having a diameter greater thanthat of said passageway and engageable with said seat, 7

said valve element having members projecting therefrom through saidpassageway and overlying the side of said ring opposite said seat toretain said element and ring in assembled relation, said projectingmembers having a length greater than the thickness of said ring topermit movement of said element relative to said ring, said carrier ringhaving two projections extending inwardly into said passageway andrespectively straddling said projecting members to steady said valveelement in relation to said ring and to obstruct rotational displacementof said valve element relative to said ring but permitting free movementof said valve element toward and from said seat, said projecting membersbeing L-shaped with the L-bends at the free ends thereof disposed tooverlie said ring.

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4. A heart valve as claimed in claim 3 wherein said carrier ring has aperipheral channel, and an outer ring of material adapted to be suturedin the opening from which the natural heart valve has been excised forimplantation of the valve.

5. A heart valve as set forth in claim 4 wherein said outer ring is heldin the channel of the carrier ring by a ring of stainless steel wireembedded in the outer ring.

6. A heart valve as set forth in claim 5 wherein the cross-section ofthe carrier ring is divergent from the inner to the outer diameter or"the ring.

7. A heart valve as set forth in claim 6 wherein the valve element is ofbiconvex form, and said projecting members on one face comprise twoeccentrically disposed upstanding columns inclined towards therespectively nearest edge of the valve element, each L-shaped bend onsaid columns being directed towards the periphery of the valve element.

8. A heart valve as set forth in claim 7 wherein said columns betweensaid element and their bends are of a length greater than the thicknessof said carrier ring, whereby the opening movement of the valve elementis effected with a movement in an axial direction, and another largermovement in a diagonal direction, in the direction of the ventricle.

9. A heart valve as set forth in claim 8 wherein said carrier ring,valve element and said outer ring are made of inert materials that areperfectly tolerated by the human body.

10. A heart valve as set forth in claim 9 wherein said carrier ring andvalve element are made of synthetic elastomers.

11. A heart valve as set forth in claim 10 wherein said carrier ring andvalve element are made of a material selected from the group consistingof polypropylene and Silastic.

12. A heart valve as set forth in claim 9 wherein said outer ring ismade of a material selected from the group consisting of Teflon andDacron.

References Cited UNITED STATES PATENTS 2,877,792 3/1959 Tybus 137527 XR3,099,016 7/1963 Edwards 31 3,113,586 12/1963 Edmark 3-1 XR 3,294,11612/1966 Tremeau 137533 XR OTHER REFERENCES The Development of AProsthetic Heart Valve Utilizing A Rigid Housing and a Fexible ButterflyWing Leaflet by V. L. Gott et al., Transactions American Society forArtificial Internal Organs, vol. VIII, April 1962, pp. 72-78 (Group335).

Evaluation of Two Prosthesis for Total Replacement of the Mitral Valveby F. S. Cross et. al., The Journal of Thoracic and CardiovascularSurgery, vol. 46, No. 6, December 1963, pp. 7l9725.

Comparative Study of Some Prosthetic Valves for Aortic and MitralReplacement by C. A. Hufnagel et. al., Surgery, vol. 57, No. 1, January1965, pp. 205-210.

RICHARD A. GAUDET, Primary Examiner.

R. L. FRINKS, Assistant Examiner.

